Don't drink like a fish. During a hangover, drink water, Coconut water, Bouillon soup, and other electrolytes and after that go to the bed and take enough rest. That's how you recover from a hangover. I have written a blog about that. You can read that, it might help you.
drink coconut water and gatorade and/or powerade to help with dehydration,usually after you have rehydrated your headache will go away,make sure you're eating too
Drink water and wait it out. If you can eat try and eat something.